They are still very niche devices, though. Onyx made a similar thing back in 2013, but they never followed up because it didn't sell well.
FWIW, I do have a Kingrow K1, and I like it for what it is, which is a 5" Kindle that can also run the occasional Android app (like, say, OsmAnd or Kiwix). It's an excellent off-the-grid device due to battery life, which is precisely what I got it for. But for business use, I don't see much point - a dedicated business device to me would be something like Cosmo Communicator or Unihertz Titan.